1. Field of the Invention
The invention relates to tandem wheel arrangements for vehicles. Such arrangements are particularly useful in off-road vehicles such as motor graders, off-highway trucks and the like. More particularly, the invention is concerned with such a tandem wheel arrangement wherein force exerted upon one of the tandem wheels is partially transmitted to the other thereof to apply reduced wheel loading to the wheel at a higher elevation while simultaneously applying greater wheel loading to the wheel at a relatively lower elevation and to reduce the upward displacement of the vehicle.
2. Prior Art
In prior art tandem wheel arrangements a problem has existed when one of the wheels is forced to a different elevation than the other. The problem mainly occurs when a motor grader is run over a semi-prepared roadbed or the like, and when one of the wheels moves upwardly as it encounters a bump or the like while the elevation of the other wheel remains unchanged. Relatively heavy transient wheel loading is thus imposed on the wheel which is at a relatively higher elevation. As a result, additional vehicle power is needed to motivate the vehicle. Further, the total machine displacement as each of the tandem pair of wheels goes over an obstacle such as a bump is relatively large, i.e., equal to one-half of the height of the obstacle, which leads to a very rough ride for an operator of the vehicle. Further, the resultant tilting of the vehice frame leads to the development of relatively large stresses therein.
Yet another problem occurs with vehicles in that one side of the vehicle may be at a lower elevation than the other side thereof. In such a situation the operator of the vehicle is at a considerable angle to the horizontal thus causing excessive operator fatigue. Accordingly, it is desirable to be able to provide height adjustment of one side of the vehicle relative to the other. While the prior art in some instances provides such height adjusting, it has not heretofore been provided in a vehicle which included means for proportioning the load between the two tandem wheels on one side of a vehicle.